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BER [Bit Error Rate]
jeet

Posts: 29

Joined: 21 Oct 2010 16:17

03 Sep 2012 15:53

BER [Bit Error Rate]

>> BER [Bit Error Rate] is a ratio of bits received erroneously versus total number of bits received



>> It is measured as follows: The test systems output signals carrying known bit patterns (usually pseudo random bit sequences or PRBS). PRBS signals are usually labeled PNx, where x is the number of bits being permutated in the sequence (such as PN9 = 29 - 1 or 511 bits)



>> For GSM, the performance is measured as follows: Digitally modulated signals power levels are set 20 dBs above receiver sensitivity at the center of the receivers' pass band



>> These signals are combined with GMSK modulated interferers. Combined signals are then injected into the antenna ports of the receivers. The power levels of the GMSK interfering signals are then set to nominal levels at which the receiver BERs must not exceed the receiver sensitivity specifications. The difference in power levels between the two signals is the interference ratio



>> The bit error rate (BER) is the percentage of bits that have errors relative to the total number of bits received in a transmission, usually expressed as ten to a negative power. For example, a transmission might have a BER of 10 to the minus 6, meaning that, out of 1,000,000 bits transmitted, one bit was in error



>> The BER is an indication of how often a packet or other data unit has to be retransmitted because of an error



>> Too high a BER may indicate that a slower data rate would actually improve overall transmission time for a given amount of transmitted data since the BER might be reduced, lowering the number of packets that had to be resent



>> A BERT (bit error rate test or tester) is a procedure or device that measures the BER for a given transmission



>> ETERNITY variants support Bit Error Rate